To start as Mar (the flute boy) talk to Sephy and Magnus then say No. Then move further along the deck and talk to Zeus and Cleo and say No. lastly, make your way back to where you came from at the entrance to the deck and a cut-scene will begin to start the game with Mar.
Defeating Gaia
Equip the Hand of Pyro and Bite of Lightning. Attack and destroy the two arms, then the white-orb. Block all the attacks Gaia does. Use Bite of Lightning to easily destroy the little robots Gaia throws at you. Do not call the Elemental Summon; you will not have enough time. When only the head remains, shoot Hand of Pyros at Gaia until he dies. Remember to block all attacks.
Defeating the Mentor
The Mentor takes some time to attack. As The Mentor raises its arms to attack you, run up to him. Attack him with your sword then quickly raise your shield. Repeat this as many time as needed. In between, use your shield. However, try not to use it too much or The Mentor will push you off the back.
Full Health
Pause the game if you are losing a battle. Then hit ''equip'' and resume the game. You will be at the start of the battle, with full energy.
Get Mar onto the ship
To get Mar on the ship, go to Sephy and Zeus. When you have a choice to let them join you, say no. Go back to the cabin area and you'll see Mar.
Regain health
If you are running low on health, just shoot or attack the Electric elementals (small wavy line of electricity). They will go away and refill your health. They will reappear soon after that, allowing you to refill your health as many times needed.
Restart a battle
Pause the game if a defeat cannot be avoided during a battle. Select "Equip" and resume the game at the start of the battle, with all energy restored.
See Sephy's underwear
When playing as Sephy, go to a side view, then jump and pause game play.
See through walls
In story mode, walk up to a wall and press L1 or R1 to see through it.